This invention relates generally to wireless communications circuitry, and more particularly, to wireless communications circuitry for handheld electronic devices with conductive bezels.
Handheld electronic devices are becoming increasingly popular. Examples of handheld devices include handheld computers, cellular telephones, media players, and hybrid devices that include the functionality of multiple devices of this type.
Due in part to their mobile nature, handheld electronic devices are often provided with wireless communications capabilities. Handheld electronic devices may use wireless communications to communicate with wireless base stations. For example, cellular telephones may communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, and 1900 MHz (e.g., the main Global System for Mobile Communications or GSM cellular telephone bands). Handheld electronic devices may also use other types of communications links. For example, handheld electronic devices may communicate using the WiFi® (IEEE 802.11) band at 2.4 GHz and the Bluetooth® band at 2.4 GHz. Communications are also possible in data service bands such as the 3 G data communications band at 2170 MHz band (commonly referred to as UMTS or Universal Mobile Telecommunications System).
To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to reduce the size of components that are used in these devices. For example, manufacturers have made attempts to miniaturize the antennas used in handheld electronic devices.
A typical antenna may be fabricated by patterning a metal layer on a circuit board substrate or may be formed from a sheet of thin metal using a foil stamping process. Many devices use planar inverted-F antennas (PIFAs). Planar inverted-F antennas are formed by locating a planar resonating element above a ground plane. These techniques can be used to produce antennas that fit within the tight confines of a compact handheld device. With conventional handheld electronic devices, however, design compromises are made to accommodate compact antennas. These design compromises may include, for example, compromises related to antenna height above the ground plane, antenna efficiency, and antenna bandwidth. Moreover, constraints are often placed on the amount of metal that can be used in a handheld device and on the location of metal parts. These constraints can adversely affect device operation and device appearance.
It would therefore be desirable to be able to provide improved antennas for handheld electronic devices.